YES (VAR X Y) (RULES f(c(X,s(Y))) -> f(c(s(X),Y)) g(c(s(X),Y)) -> f(c(X,s(Y))) ) The TRS is an overlay system and all critical pairs are trivial, thus termination of innermost rewriting is equivalent to termination of rewriting. Proving termination of innermost rewriting for test829: -> Dependency pairs: nF_f(c(X,s(Y))) -> nF_f(c(s(X),Y)) nF_g(c(s(X),Y)) -> nF_f(c(X,s(Y))) -> Proof of termination for test829_1: -> -> Dependency pairs in cycle: nF_f(c(X,s(Y))) -> nF_f(c(s(X),Y)) There are no usable rules. Polynomial Interpretation: [f](X) = 0 [c](X1,X2) = X2 [s](X) = X + 1 [g](X) = 0 [nF_f](X) = X TIME: 4.3329e-2 SETTINGS: Base ordering: Polynomial ordering Proof mode: SCCs in DG + base ordering Upper bound for coeffs: 1 Rationals below 1 for all non-replacing args: No Polynomial interpretation: Linear Coeffs in polynomials: No rationals Delta: automatic Termination was proved succesfully.